1. Field of the Invention
The present invention relates to a spark plug.
2. Description of the Related Art
In order to increase the durability of a spark plug, hitherto, a noble metal tip has been joined to a ground electrode of the spark plug. For example, as with a spark plug described in Japanese Unexamined Patent Application Publication No. 2015-22791, if the noble metal tip protrudes from an end of the ground electrode, a sparking location can be concentrated at the end of the ground electrode, so that it is possible to increase the durability and ignitability.
However, in recent years, in order to increase fuel economy performance, the fuel has been made leaner and supercharging has been performed in an internal combustion engine. Therefore, the spark plug is required to provide even higher ignitability to allow reliable ignition even when the spark plug is used in such an internal combustion engine.